1. Field of the Invention
This invention relates to a light collector and, more particularly, to a device for sampling light in an area illuminated in part by artificial means and producing an output adjustably dependent upon the level of intensity of the light present in that area.
2. Description of the Prior Art
The cost and relatively limited supply of resources needed to supply electrical power to commercial, industrial, and residential structures has forced owners and tenants of such structures to seek ways of minimizing the electrical power consumed by various systems needed to operate them.
Attempts to reduce the electrical power consumed by lighting systems range from using sophisticated electrical devices to simply removing a portion of the light sources from the lighting system.
One such attempt involves the use of a control system for maintaining the light illumination of an area constant by comparing the actual light intensity within the area to the desired light intensity therewithin and adjusting the amount of light produced by the lighting system if a difference exists between the actual and desired light intensities. Accordingly, when sunlight enters the area, thereby raising the illumination thereof, the system reduces the amount of light produced by the lighting system, thus reducing the amount of electrical power consumed thereby. Such a system includes apparatus for collecting light present in the area, a device--such as a photoresistor--for converting the output of the collector to an electrical signal related thereto, a device for providing an electrical signal representative of the desired light intensity within the area, a device for comparing the signals related to the actual and desired light intensities and generating an error signal related to the difference therebetween, and a device for modifying the output of the lighting sources in response to the error signal.
One collector that can be used in a system for controlling the light intensity in an area is sold by Prince Products, 78 Prince Street, Brooklyn, New York 11201. One disadvantage associated with such a collector is that the illumination level maintained by the control system within the area can be changed only by gaining access to a portion of the system that is usually hidden from the view of a person in the area. For example, if the collector is located in a suspended ceiling, the user must disassemble a portion of the ceiling to change the illumination level within the area. Accordingly, such a change can be made only at some inconvenience to the user.
Therefore, a need exists for a light collector for use in an illumination control system that enables a person to adjust the illumination maintained thereby conveniently and quickly.